In fishing with a fishing reel, the fisherman determines the desireable size of fishing line by taking the kind and size of fish bein fished for into consideration. The drag brake force is generally set by adjusting a spool to a value which is suitable for the pulling force of a catch and the tension withstanding strength of the fishing line.
In a typical conventional drag brake device, a friction board is clamped with brake boards. A coil spring to bias the brake boards to the friction boards is provided in an adjusting cylinder. In a low drag brake condition, the coil spring is used to push the brake boards. For a high drag brake condition, the end face of the adjusting cylinder itself is used to push the brake boards. The resultant drag brake force F with respect to the advancing angle G of the adjusting cylinder is as indicated by the braking characteristics curve C in FIG. 5. In the former case, the drag brake force is maximum with an angle .alpha.; and in the latter case, it is maximum with an angle .delta.. Thus, the conventional drag brake device suffers from the disadvantage that the drag brake force is abruptly changed at the point where the two angles are switched.
Furthermore, a drag brake device has been proposed in which a friction board is interposed between brake boards, a leaf spring abutted against the front brake board is pushed with a lever and a cam plate, and the front end face of an adjusting cylinder is used to push the rear brake board in order to adjust the brake force. The device operates according to braking characteristic curves D and E in FIG. 6, each of which forms an angle .beta.. When the adjusting cylinder is loosened, the device operates according to the curve D, and when the adjusting cylinder is tightened, the device is operated according to the curve E. Thus, with this device it is impossible to obtain a moderately sloped braking characteristic curve providing a weak drag brake force.
Thus, as can be seen, the conventional drag brake device is disadvantageous in that the drag force adjustment is rather difficult.
The drag brake device of the present invention is constructed to overcome the problems as described above. Therefore, although the device is simple in construction, a smooth braking characteristic curve can be obtained, and a wide range of drag brake forces can be readily obtained by operating a drag adjusting knob and a drag adjusting lever. Furthermore, a most suitable range of drag brake forces can be determined according to the kind and size of fish desired to catch and the size of a fishing line used. Accordingly, the application of an improper drag brake force to the reverse rotation of the spool shaft is prevented, and the occurrences of fishing line being overstressed during fishing will be minimized. Thus, the drag brake device provided according to the invention for a fishing spinning reel should be highly appreciated in practical use.